Had a nam go down (unknown release) and it was on a mics 5.0. replaced the nam with a 4.0c 8 channel and everything works except outside calls after hours you can ring the station number but does not go to the station voicemail. just blank recording and then say exiting the system. Have two nam and both do the same thing, but if I put them on a mics 4.1 release no problems at all. all my charts say the 4.0 is compatable with miscs 5.0 and down. have looked at software releases and cannot find any difference between the 4.1 and 5.0 in addressing nam voicemail releases. any answers.............telco 71